Draft control device



Feb. 13, 1934. i w BUTLER ET AL 1,946,568

DRAFT CONTROL DEVICE Filed Dec. 7, 1931 2 Sheets-Sheet l l/Wo m Feb. 13,1934.

W. L. BUTLER ET AL DRAFT CONTROL DEVICE Filed Dec. 7, 1931 2Sheets-Sheet 2 anal UNITED STATES DRAFT CONTROL DEVICE William L. Butlerand Henry F. Hillard, Salt Lake City, Utah; said Hillard assignor tosaid Butler Application December '3, 1931. Serial No. 579,484

1 Claim. (01. 23645) Our invention relates to draft control devicesFigure 7 is a section of the support block on and has for its object toprovide a new and efline '77 of Figure 2.

ficient control for controlling the draft in a fur- In the drawings wehave shown our device as nace pipe, preventing back draft, and keepingthe made of a rectangular casing A, having an inlet pull from thecombustion chamber constant. pipe 1 in one end thereof and an outletpipe 2 in 00 A further object is to provide a device for regutheopposite end thereof and with a partition 3 lating the draft in furnaceswhich by automatic dividing the interior into two chambers B and C.action prevents reverse or back draft, opening The partition 3 issecured to the top of the casthe draft from the furnace into thesurrounding ing box A and extends down to near the bottom atmospherewhen there is a back draft in the flue. 0f the box where it is bent atan angle with the B5;

Astill further object is to provideadraft control bent side 4 parallelto the base of the box and which will save fuel for the user and whichelimithe bent side is then secured to the inlet end 5 nates the dangerof asphyxiaton due to blowing 0f the box A below the level of the inletpipe 1. out of the flame and allowing the gas to escape In the bottom ofthe box A under the partition 4 unb ed we provide an air vent 6 andadjacent to the vent 70 A still further object is to provide a constantWe provide tWO Spaced apart V t ca rods 7 draft in the combustionchamber to furnish oxywhich rods carry a closure plate 8 with e p ategen for combustion in a constant quantity result- 3 Over the Vent 6 andWith elongated S ots 9 n the ing in the fuel being completely burned,effecting P e 8 around the rods 7 50 that When the plate savings verother methods now used ls ralsed Suction the bOX the plate raise A Stillfurther object is to provide a flue draft without friction as the slots9 will allow the plate control which will draw relief air from thefurnace to ralse on h rods 7 Wlthout touchmg them in room into the stackonly when the fire is burning, x and m Order 1 that the plate 3 and thenonly in the exact amount necessary to @1565 Wlth h back slde hlgher thanthe frnt maintain the minimum required draft pull on the slde Weprovlfie i Welght 10 on the slde of so orifice the plate 8 in which theholes 9 are formed.

A still further object is to provide a balanced Through the top A1 Ofthe casmg A We then control for controlling the flow of draft from thevlde ouflefi opemng or PQ 11 and h furnace through the flue, preventingback draft ggg lgg g gj gf f t gg g g i fi s g 8 by f g g the flue ifurnace i Vhen closure device D mounted thr ugh of; tc i g e the 5 backa occurs an provi ing a prac Ica y rictionless control eliminating thenecessity of undue 2 :2 3 3 2 55 ggg'gg gzfiii gigg gfizi fig.

suction or back draft being necessary to operate the other polit is openAn adjustable plate 15 the device.

These objects we accomplish with the device ilif ggg 32 23 95??? 3 5 2 aga bifi 9o lustrated in the accompanying drawings in which from thechamber B into the chamber 0 This s milar numerals and letters ofreference indicate is Set when the device is installed by making thelike pa throughout theseveral Yiews and as draft the correct pull forthe fire being used and 7 described i t Speelfieetloh fol'mmg a Part ofthe plate 15 is then looked in place by the bolts 95 this applicationand pointed out in the appended 16. claims. In the d a in which We haveShown The plates 13 and 14 of the closure D are made the best and mostpreferred manner 01' building as shown, at an obtuse angle to eachother, but our invention. they do not necessarily have to be made atsuch an Figur 1 is a Perspective View Of the device, Darts angle.Dividing the space between the two plates 100 ShOWIl by dotted lines andparts shown 0111', away. into two equal angles and extending outwardly Il Figure 2 is a plan view of the device. therefrom we provide a counterbalance rod 1'7 Figure 3 is 61 Vertical Section on line of carrying anadjustable weight 18 with a set screw Figure 2. 19 provided for settingthe weight at the proper Fi 4 is an end View Of Figure position forbalance of the two plates. On the 105 Figure 5 is a side elevation ofthe pivoted conback side of the two plates at their juncture we 7 trolplates provide spaced apart support blocks 20 and 21,

Figure 6 is a plan view of the plate for covering one at each edgethereof, said blocks being prothe draft regulation opening in the bottomof the vided with threaded holes therethrough, through device. H whichholes we provide adjustable externally 1119 threaded pivot points 22 and23, which points are carried in blocks 24 and 25. The said blocks 24 and25 are mounted on the top side of the box A adjacent to the opening inthe top thereof and said blocks are provided with tapered indentations26 in the top side thereof in which the pivot points rest to support thetwo plates pivotally in the openings. The weight and rod extend upwardlyand toward the outlet end of the box A. The plates are set in the deviceand the weight adjusted to close the port 11 and at such abalancedposition that draft through the device will not afiect the port but sothat back draft will instantly close the port 12 and open the port 11allowing the consumed gases to escape from the box A through the port 11into the room around the furnace.

The operation of the device will be as follows:

When the draft in the stack is equal to or lower than a predeterminedrequired amount which is fixed by the weight of the vent plate 8,exhaust gases from the combustion chamber of the furnace will passthrough the inlet pipe 1 into the chamber 13, through the port 12 intothe mixing i chamber C and out to the stack through the outlet pipe '2.

When the draft of the stack. is greater than a predetermined requiredamount which is fixed by the weight of the plate 8, exhaust gases willpass through the chamber B through the port 12 into the chamber B andout through the port 11 into the surrounding atmosphere. The back draftwill close the port 12 by pressing the plate 14 thereagainst, or if thedraft condition is neutral the buoyancy of the gases from the furnacewill lift the plate 13 closing the port 12 and opening port 11. Tonormally adjust the proper amount of gases from the combustion chamberof the furnace and carry them out the stack a certain definite draftmust be maintained in the chamber B and this is controlled by the sideof the port 12 by the plate 15. The intensity of draft in the chamber Cis maintained by the opening of the vent 6 by raising the plate 8 by thesuction in the chamber. Any increased velocity or suction through thestack will open the plate 8 more from the vent 6 admitting relief airinto the chamber C.

With this device connected between a stack and outlet of any combustionchamber the air and fuel supply to the combustion chamber may have theirrespective controls so set that proper combustion is effected whenexhausting all of the products of combustion through the opening 11. Atthis condition there will be uniform absolute pressure in the chamber B.To normally discharge the products of combustion to the stack the portthrough the partition 3 and the weight of the vent plate 8 are soadjusted that the controlled degree of draft in the chamber C will bethat degree necessary to permit just the proper flow of gases throughthe port 12 to maintain the same absolute pressure in the receivingchamber B as when the products of combustion all passed through the ventor opening 11. With such a setting the products of combustion may freelyexhaust into the furnace room through the port 11' discharging onlyharmless carbon dioxide and water vapors therethrough.

A rotating balance is maintained in the plates 13 and 14 and the weight18 by proper adjustment of the said weight on the rod 17.

When installing the device the plates are adjusted to a rotating balanceand the pins are then slightly withdrawn so that the weight willnormally close the port 11 and leave the port 12 free.

Having thus described our invention we desireto secure by Letters Patentand claim:

A draft control for furnaces "comprising a caslng divided into inlet andoutlet chambers with a port therebetween and with a port from the inletchamber into the atmosphere; pivota-Ily supported integralcounter-balanced plates carried on said casing adapted to close theatmospheric port and open the port between the chambers or open theatmospheric port and close the port between the chambers as the draftthrough the furnace flue fluctuates; and a draft responsive platecontrolling a vent in the outlet chamher to draw extra air into theoutlet chamber when the draft through the flue is increased above thatpredetermined amount required for complete combustion in the furnace.

WILLIAM L. BUTLER. HENRY F. HILLARD.

